The Yemeni army killed a Shiite rebel leader in the ongoing clashes in the north of the country, in which dozens of troops and rebels also died, government sources were quoted on Monday by Reuters. Fighting escalated Monday with the rebels claiming to have made a number of advances, including taking control of several strategic areas in the northern Saada Province which borders Saudi Arabia.

The Shiites also stated they launched Katyusha rockets on an army camp in Saada and vowed more strikes in the future.

Their claims came after Yemen’s defense minister confirmed the offensive by government troops had paralyzed the rebels’ movements and dealt them a severe blow. A government official told Reuters that Hussein Kamza, who led rebels in the northern Amran Province loyal to Abdul-Malik al-Houthi, was killed during fighting on Sunday. The defense sources added that many districts in the province were cleared of Houthi rebels and their weapons stores destroyed.